Ashford sits on a complex geological patchwork where the stiff, shrinkable Weald Clay meets pockets of Quaternary river terrace gravels along the Great Stour corridor. In wet winters the groundwater table can rise to within 1.5 m of the surface across the low-lying parts of the town centre, and the clay shrinks noticeably during prolonged dry summers, creating a subgrade that tests any rigid pavement designer. A CBR road assessment is often the first step, because the soaked CBR values we have recorded in the clayey zones south of the railway works rarely exceed 2–3%, which forces a deep re-evaluation of slab thickness and joint spacing if the pavement is to meet its design life without uncontrolled cracking.
Good rigid pavement design in Ashford is less about concrete strength and more about controlling what happens in the first 600 mm beneath the slab.
